Float-operated level control

ABSTRACT

A SPREADER BOX FOR CONTAINING GELATINE TO BE CAST INTO RIBBONS OR SHEETS ON A CASTING DRUM INCLUDING A FLOATOPERATED VALVE CONSISTING OF A HOLLOW CYLINDRICAL ROTARY VALVE MEMBER AND A CYLINDRICAL FLOAT PARALLEL TO THE ROTARY AXIS OF THE VALVE MEMBER AND CONNECTED THERETO SO THAT ANGULAR MOVEMENT OF THE FLOAT ABOUT SAID AXIS IS TRANSMTTED TO THE VALVE MEMBER. THE VALVE MEMBER HAS AN   APERTURE IN ITS SIDE WALL WHICH COOPERATES WITH THE END OF A STATIONARY FLOW PASSAGE TO LIMIT THE FLOW OF GELATINE INTO THE SPREADER BOX. THE FLOAT IS ROTATABLE MANUALLY BEYOND A POSITION ABOVE THE ROTARY AXIS OF THE VALVE MEMBER TO CLOSE THE VALVE.

May 25, 1971 M. K. MEHTA FLOAT-OPERATED LEVEL CONTROL Filed May 27, 1968United States Patent 3,579,734 FLOAT-OPERATED LEVEL CONTROL Maharaj K.Mehta, Cardiff, Wales, assignor to P. Lerner & Sons (Encapsulati0ns)Limited, Treforest, Glamorganshire, Wales Filed May 27, 1968, Ser. No.732,201 Claims priority, application Great Britain, July 18, 1967,32,919/ 67 Int. Cl. B29d 7/02 U.S. C]. 18-15 4 Claims ABSTRACT OF THEDISCLOSURE A spreader box for containing gelatine to be cast intoribbons or sheets on a casting drum including a floatoperated valveconsisting of a hollow cylindrical rotary valve member and a cylindricalfloat parallel to the rotary axis of the valve member and connectedthereto so that angular movement of the float about said axis istransmitted to the valve member. The valve member has an aperture in itsside wall which cooperates with the end of a stationary flow passage tolimit the flow of gelatine into the spreader box. The float is rotatablemanually beyond a position above the rotary axis of the valve member toclose the valve.

This invention relates to a float-operated level control for restoringthe level of a liquid to a predetermined level. The invention isparticularly suitable for use in a spreader box which contains gelatinefor casting into ribbons or sheets on a casting drum.

Known ball-cocks have disadvantages when used With liquids of highviscosity, such as gelatine, due to high frictional and viscous forces,which tend to make the control of the liquid level inaccurate.

According to the invention there is provided a floatoperated valve forrestoring a liquid level to a predetermined level, comprising a flowpassage through which the liquid flows to alter the liquid level, arotary member having an orifice for co-operating with the flow passageto pass the liquid which flows through the flow passage, a floatconnected to the rotary member for rotating the member to a positiondifferent from its normal position in accordance with the difference ofthe liquid level from the predetermined level, and the co-operationbetween the orifice and the flow passage being dependent upon theposition of the float, whereby the rate at which liquid is passedthrough the orifice is controllable.

An embodiment of the invention will now be described, by way of example,with reference to the drawings, in which:

FIG. 1 is an elevation, partly in cross-section, of a spreader boxemploying a float-operated valve embodying the invention, and

FIG. 2 is a cross-sectional view taken along the line 2-2 of thespreader box shown in FIG. 1.

, The spreader box illustrated has two spaced parallel side walls 11 and12, a front wall 13 in the form of an adjustable doctor blade, and arear wall 14 sloping downwardly towards the front of the box. The rearwall 14 carries at its lower end a resilient bottom plate 15, whichpresses against a casting drum 16. The box has a floatoperated valve 20mounted on the side wall 11 and connected to an inlet pipe 17, and anoutlet '21 which is the slit between the bottom of the doctor blade 13and the drum 16.

The spreader box is designed for supplying gelatine to the casting drumfor casting ribbons or sheets of gelatine. As the drum 16 rotates in thedirection of the arrow in =F-IG. 2, a sheet 22 of gelatine is formed onthe surface of the drum 16. The thickness of the sheet depends on the3,579,734 Patented May 25, 1971 speed of rotation of the drum 16 and theposition of the doctor blade 13, which is adjustable by a captive screw24.

The valve 20 is controlled by a cylindrical float 25, the side of whichis attached to a rotatable bar 26 for rotation about the axis thereof,which is parallel to the longitudinal axis of the cylindrical float. Thebar 26 is connected at one end to a length of hollow cylindrical tubing30, and at the other end is supported by a bearing 33 mounted on theside wall 12. The tube 30 is closed at both ends and has two holes ororifices 31 and 32 in its side wall. The inlet hole 31 is arranged sothat when the float 25 hangs down vertically (position A in FIG. 2) theinlet hole 31 fully co-operates with the end of the inlet pipe 17. Theoutlet hole 32 discharges directly into the spreader box.

FIG. 2 shows three positions of the float. Position A is adopted whenthe liquid level is low, and the valve 20 is fully open, as describedabove. As the box fills, the float 25 gradually rotates, causing thetube 30 to rotate also, and thereby reducing the rate of flow ofgelatine into the box, until the gelatine has reached a predeterminedlevel, at which point the float is in the steady position B and the rateat which gelatine enters the spreader box through the valve 20 equalsthe rate at which it leaves the box through the outlet 21. It issometimes desired to empty the tank or close off the valve 20 for someother reason, and to do this the float has only to be rotated manuallybeyond the vertical to position C. The ease with which the valve 20 canbe manually turned off completely makes it more convenient than aconventional ball-cock, as it may obviate the need for a tap orstop-cock.

The shape of the orifice 31 and the end of the inlet tube 17 can bealtered so that any desired cut-off law can be employed, thus varyingthe permissible limits for the liquid level in normal operation.

The valve 20 illustrated is particularly useful for use with gelatine,since the cutting action of the tube 30 as it rotates is not affected byfrictional and viscous forces as much as a conventional ball-cock wouldbe. With less viscous fluids, it may be necessary to provide a seal toensure that no fluid passes when the valve is closed.

I claim:

1. In combination with a spreader box for containing a gelatinous liquidand having an orifice for cooperation with the surface of a casting drumto form a sheet or ribbons on the drum due to liquid discharged throughsaid orifice, said box having a pair of spaced walls, a float-operatedinlet valve means for controlling flow of liquid into said box, saidvalve means comprising a rotary valve member rotatably supported on oneof said walls, an elongated substantially cylindrical float ofsubstantially large diameter disposed within said box and positionedsubstantially parallel to the rotary axis of said valve member andconnected to said valve member so that small vertical movement of saidfloat about said axis causes comparatively large angular movement ofsaid valve member, and bar means positioned on said rotary axis forfixedly connectin said float to said valve member, said bar means beingdisposed closely adjacent the periphery of said cylindrical float andhaving a first portion fixed to said valve member and to said floatadjacent one end thereof, and said bar means including a second portionrotatably supported on said other wall and connected to said floatadjacent the other end thereof.

2. The combination according to claim 1, wherein said bar means includesan elongated bar extending between said walls and disposed directlyadjacent and attached to the external periphery of said float.

3. The combination according to claim 1, wherein said float is rotatablemanually beyond a position vertically above said rotary axis to closesaid valve means.

r 3 4 4. The combination according to claim 1, wherein said 2,775,25712/1956 Stirn et a1. 1815X valve member comprises a cylindrical tubelying on said 2,996,222 8/1961 Botkin 222-67 rotary axis and having anaperture in its sidewall for 3,357,052 12/ 1967 Vos 18 15 cooperationwith the end of a stationary inlet flow passage 1 in dependence upon theposition of said float. 5 J, SPENCER OVERHOLSER, Primary Ex inReferences Cited M. O. SUTTON, Assistant Examiner UNITED STATES PATENTSUs CL 1,650,806 11/1927 Slaten 22267 222-67 2,714,976 8/1955 Sucksdorif22267X 10

